AC180 solar panel series limit

I have 4, 100 watt 24.5 volt solar panels. In series and parallel. Works fine… When I try to add another panel to each set of panels in series its doesnt work. also tried to directly hook up 3 of the solar panel in series and that doesn’t work. What causes this… does going over the 60 volt DC input with 3 panels at 24.5 volts in series trip a safety in the AC180.

@FERGMAN yes, going over the max OCV/VOC will overload and potentially damage your 180, which isn’t covered by warranty. In fact, it’s best to only go to 90% of the max, say 54v, to allow for voltage increases in cooler temperatures. OCV/VOC is the voltage you need to add up for each panel when in Series, not VMP voltage, which is usually lower.

@FERGMAN For AC180, the solar charge voltage range is 12-60V (OCV: open circuit voltage 35V-150V), max.500w (actual input solar power after conversion).
When you choose the solar panel, connect the panels in series or parallel, pls make sure it meet above requirements.
Voltage lower than 12v or above 60v which will trigger low-voltage/over-voltage protection, total input solar power exceed 500W, AC180 will only absorb 500W.

24 X 3 = 73.5 which is greater than the 60 volt DC input limit you mentioned.

You need to find a combination of wiring to get you close to the Voc rating of the AC180, but not over it. Use the Voc listed on the back of the panels, NOT the other listed voltages.

You will also find that the panels never produce their rated wattage, so you have to over-panel, again without exceeding Voc. (Going over wattage or amps doesn’t matter). I have 18 - 100 watt panels, with 3 strings of 6 panels each string. So it took 1800 theoretical watts to get to 1500 REAL watts for my AC500.

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I wonder if you are not facing the 15A limit of the solar input. Beyond 15 amps of your panels, your ac500 will limit you to 15A. I believe that for your bifacial panels, the intensity should increase (production of the other side) a lot compared to that for one side: thus you can exceed 15A and be limited to 15A!

Renogy’s specs for the 550W Bifacial is 14.05A Isc (that would be the MAX amperage).
Wired in series the amps will never exceed 14.05A. The highest I’ve seen with my Ammeter is around 12A; average is around 10A.

Hello. I believe that the power and isc and impp for a bifacial panel is given assuming that the back face produces nothing. However if the back face produces for example 20% more power (compared to the max power given for the main face) this translates into a 20% increase in the impp or isc given in the specifications. You are right to measure with the ammeter to be sure, the day you will have full sun!

I’m not seeing a 20% increase. Here’s a screenshot today, (The 2nd array) one of the few times it produced more than 1300W. It normally lags behind my 1st array of 18-100W panels by 200-250W.
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I didn’t have enough room to build another 18 panel array; it would have been better and cheaper than the Bifacials. Cheaper because Amazon was selling them in pairs for $75, so $675 for the whole array.

There are a few things that seem strange to me about your bifacial panels and your ac500. And that bothers me! :thinking:
First observation: your two bifacial panels in series in direct sunlight should give 13.11A for the front side + a few amps for the rear side. However, I have the impression that your rear side does not produce any power at all (0 amp) and is completely covered. It is not normal.
Second observation: if we take your dc2 figures: 1316w and 101.2V, let’s calculate the amps =1316/101.2=13.004 A… :astonished: I don’t think it’s a coincidence that it falls on 13A almost exactly. I have the impression that the intensity has been capped at 13A on DC2. While the manual says it’s 15A maximum.
When we combine the two observations above I say to myself that your ac500 has limited the intensity on dc2 to 13A…
The situation on dc1 seems better: 1497/111.7 = 13.402 A.
You know what, I will try to invert dc1 and dc2: that is to say you connect your renogy panels to dc1 and your other panels to dc2 and see if that gives the same figures. If your renogy panels start to give more power on dc1… It means you have a problem on dc2.
This is all a bit far-fetched, but it’s through experimenting that we discover things :exploding_head: (or nothing at all! :rofl:)

I would add that you are still close to the maximum limit of 3000W of the solar input of the ac500, you can grab 200w more at maximum

Well, it’s possible of course.

Hmm, I tried connecting only 1 panel to DC2, upside down, flat on the ground at high noon.
Then I flipped it right side up, in the same spot just minutes later.

While the backside shows 250W, the front side is only 395W.
With 3 in series producing 1330W, a single panel should produce about 440W.

So, each panel is 395W with the extra coming from the backside? The placard says 550W max. Yeah, if you install a giant mirror underneath. If the backside gets very little light you’re stuck with only 395W per panel.


I’m puzzled by your test, but it does help with the diagnosis!
The image below of your panels clearly shows that 550W is the maximum power generated by the front panel alone… and that the rear panel can give up to 30% more, i.e. 715W. It’s not normal that in full sunlight and at midday, your panel only gives 395W when it should give at least 550W.

Either the panel is damaged, or it’s false advertising (which would be surprising, as RENOGY has a good reputation…), or the AC500’s mppt or the AC500 has a problem.

Unless, in the configuration of the DC1 and DC2 ports, DC2 is not positioned on PV ? see the image below.
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